Glyc Prewashing

[dgs]

Yes, thats correct.
With the oil titrating so high I am not sure if 5 gms/litre of oil would do it, but try. If you have to add more, then do. The important thing is to have the oil non-acidic before you add the methoxide, so any water created from the FFA neutralisation is done during the glyc wash stage and therefore is removed by the glycerol. If it is easier for you the koh/methanol (methoxide) can be added after the glycerol. you just have to remember that you will lose the FFA portion of the oil (which is about 50% of titration) so about 5 litres when doing any of these methods.

I will try to send a link to the caustic stripping.http://biodiesel.infopop.cc/eve/forums/a/tpc/f/5367078823/m/3897002473/p/4

To save time the charts you need are on page 4 and the experiment I did with the oil that titrated at 21 is on page 6

The biggest drawback with this method is that after the stripping process you have to dry the oil, whereas using the glycerol method the glycerol does the job for you.

[willbuild]

Have done another 100 ltr batch.pre washed with 25 litres of glycerol with 5 litres of method and 5gr per litre of Kohl.
Leftover night to settle. Next morning I did a 10/90 test and had no conversion.
 So did my 1st stage, 7 litres of meths and 7gr per litre kohl.
10/90 test gave me a fall out of 4.5 ml. Added  3 litres of meths and 5gr per  litre of Kohl to get a clear pass.
1st 100 litres batch needed 18gr per litre.
2nd 100 litre batch 17gr per litre.
1st batch produced 68 litres of bio.
2nd batch produced 88 litres of bio.
Both batches where done with the same oil.
 

[dgs]

Thats a good result willbuild.
Although the KOH amount used is similar the yield of bio, some 20 litres more is a massive increase.

Because most of the FFA's have been removed with the glycerol present, when your methoxide was added far less water would have been produced and less product lost to saponification.

I still think you could improve by adding even more KOH/methanol to the mix when the glycerol is in there, add enough so the oil is alkaline if you try to re-titrate it.

Nevertheless a good result, Well Done.

[willbuild]

I will set up to titrate, I did titrate when I first started two years ago but have not done since.
I will repeat the process in a few weeks time.
Am I right in thinking that the 1st stage glycerol will not be as high in water content as only 7 gr per litre of kohl was used in the first stage. Normally my 1stage has 15gr per litre.

[dgs]

It is the other way round, the 1st stage glycerol is higher in water as this is when the FFA's are neutralised producing soap and water. That is why when calculating chemical requirements for the second stage from the result of the 10/90, the residual amount of oil should be treated as new oil,ie only adding the base amount of KOH for full conversion.

The glycerol enhancement method is actually like an extra 1st stage, so if you get the oil to slightly alkaline before the 1st 'normal' stage, then in thoery the rest of the oil will convert on @ 8gms/litre.

Dave.

[willbuild]

Processed an oil last week with a titration of 25 so I tried caustic striping at 4grs per litre of naoh and 4 lts of water for 100 lts of wvo.
After drying the oil the titration turned red with just 3 drops of fluid.
I then processed in 2 stages using 8grs of Kohl per litre with a conversion of 87%.
Had 80 litres of wvo with a value of 45, so stripped last night using 4grs of naoh and 4lts of water and left overnight.
This morning after drying it had a value of 12.
Did a enhanced glycerol wash with 8grs per litre of Kohl and 3 litres of methanol, did a 10/90 test with no conversion.
After 3 stages I have a clear pass having used 9grs per litre.
Glycerol is back in and has had water wash and am waiting for it to settle and will then see what the conversion rate is.

[dgs]

Hi willbuild,
Those seem very good results for oil titrating so high. Are you titrating with KOH or NaOH. Here is a link to IMB's chart where he gives the amount of NaOH for various titrations, If the link shows all the thread the chart is on page 4.

                                                 http://biodiesel.infopop.cc/eve/forums/a/tpc/f/5367078823/m/3897002473/p/4

The conversion rate on your 25 titration batch is excellent, you have only lost the FFA portion of the oil. If the batch titrating at 45 is similar you will get @ 77% yield.

Where on earth do you collect oil from that titrates as 45?

[willbuild]

Fed in 75 lts of wvo and have 60 lts of.bio i think  thats 80%.
I get the oil from a fried chicken take away, it's colour is a dark brown almost black. There oil normally titratates at around 25.
I normally pick up 60lts every week off them but they left the oil change 10 days on this occasion.
My titration fluid is naoh, when measuring the 1gr I use a scale that measures to two decimal places.

[dgs]

There is something that doesn't add up with your figures willbuild.

Don't get me wrong, not criticising, just a comment.

When we titrate with KOH roughly 50% of the titration is FFA%. When using NaOH roughly 70% of the titration is FFA%
So your titration of 45 means there is @ 32% FFA's present which would be lost to soap and water either during the stripping stage or the base stage. This means that if the rest of the process was 100% efficient the maximum yield you could have would be 68%, yet you have ended up with 80%

Are you sure your titrant is correct and did you blank your IPA before adding your sample. IPA can be quite acidic.

[willbuild]

Yes I do blank it, it takes only 3 drops  for ipa to turn red after adding the turmeric.
A few weeks ago I titrated a sample of new oil to see what the result would be and found that with just 3 drops of fluid it went from yellow to red.
My  solution is about 3 months old and my ipa about  10 or 12 months old.

[dgs]

Hmm, I'm puzzled. But then I'm always puzzled about something.

[BANDIT2]

Sent you a pm Simon...
Oh, and hello you lot, I'm back!

[Tony]

'ello! Ow bist?

[BANDIT2]

I'm fine Tony ta
I've never really really been away just forgot my log on details but have been lurking a lot.
It went real quiet on here but has pepped up a lot recently- good stuff